Purposes are to establish the qualitative and quantitative toxicity of CI-980 when administered to children whose tumor is refractory to standard therapy; to establish a maximum tolerated dose of CI-980; and to determine the pharmacokinetics of CI-980. CI-980 is administered as a 72 hour continuous IV infusion every 21 days. The patient will be evaluated for response every 21 days. If there is response and no unacceptable toxicities are experienced, the patient may continue receiving therapy for up to one year. The starting dosage is 3.5 mg/m[2]/day for 3 days. The study coordinator for the protocol will assign the dose level for each patient. Hospitalization is required while the patient is receiving the 3 day infusion. Upon completion of the infusion, the patient will be followed as an outpatient for weekly physical exams and lab work 2-3 times a week. All patients or their legal guardian must give informed consent before starting treatment.